Can you enable the debug plugin? Is there something shown which takes a lot of time?

I enabled the caching option and gzip and it looks like the loading time is stable now. Debug log did not show anything importent.

Good to hear.

I am sorry but i have to reopen this thread. I first was thinking the page is loading better but it looks like its not gone.
So the confusing stuff is that Phil from myJoomla tested the loading of the page and for him there was no problem with the loading time. From my mobile phone its running with good loading times just from my home connection its that slow. I also tested it with a friends network and there i have the same problem. I am using Cloudflare for the page so loading time should be no problem at all.

My internet connection can't be the problem because all other pages are loading fast without the issue. I already restarted the network from Unitymedia to get sure it has nothing to do with it.

I already tested 4 browsers and also cleared the cache with no luck.

The cache plugin is disabled already and the file is replaced as the faq tells because of the cache problem of 3.7.

I already replaced all joomla 3.7 files from zip to get sure nothing is missing.

Database structure is fine i checked it with joomla if there are any errors.

PHP Version: 7.1 (CGI): this is the latest php version i can activate by my hoster. But it was running well with this version before the update.

PHP_Errors none: i logged them to a log file and none are coming up on the server side. Also on the page i enabled display errors maximum and none are shown.

Database query frontend:
56 ausgeführte Abfragen 14.67 ms

Storage usage frontend:
16,27 MB (17.056.128 Bytes) (Is this the page size? I cant believe the page is that big)

Loading chrome info:

Debug loading info frontend: 17.17s seconds

Database query backend:
47 ausgeführte Abfragen 126.89 ms

Storage usage backend: (Why is that so high its the standard isis template..)
14,60 MB (15.310.488 Bytes)

Debug loading info backend:

So backend loads same slow as frontend so i dont think its the page content.

All images on page are optimized with tinyjpg and tinypng.

@laoneo what exactly do you need from the debug log to see if there is a problem?

Edit:

JCH optimize added to shrink css, js and html to minimal size.

Cloudflare shrink for css, js and html also enabled.

I really dont know how to optimize it more to get my old speed back.

Tried to change php version to smaller one with same reseult.

Have you tried to uninstall JCH Optimze other system plgs and see the results?

Pls check with JCH Optimize to send in a support ticket to them or post in their forum about problem if you have these Joomla 3pds performance plgs and components.

I installed JCH after the problem to check if it can solve the problem.

Have you tried to make a fresh Joomla install on that hosting environment and see if that have the same problem?

With a fresh install it was working well.

After hours of searching the problem i disabled cloudflare for the subdomain where the problem is located and the page is loading fast again. Looks like i have to contact cloudflare so they can tell me why this problem happens.

Did you flush Cloudflare cache "everything" for your domain there also?

Yes many times before on joomla and cloudflare. I now ended up with disabled cloudflare and because of the try to optimize the page for hours now its much better as before. Without the error i never had optimized it that much ? . So hope to get a reply from cloudflare soon because i still would like to use it.

cloudflare is very hard to get working on a subdomain

@brianteeman good to know... I never noticed that but i must say that i never used cloudflare on a subdomain to develop a page. Good that i switch the page to the normal domain as soon as its done.

Just to show the difference without cloudflare enabled xD:

Cloudflare: (Check loading time on bottom)

Without Cloudflare: (Check loading time on bottom)

Try to disable Mootools.